Elastic semiconductor single crystal, method of production and electroluminescent applications thereof

Abstract

This invention discloses the chemical structure of an elastic semiconductor single crystal material and its preparation method. For micro-sized crystals based on this material, the application and fabrication process of electroluminescent devices based on it are also disclosed. This material possesses excellent elasticity and flexibility, filling the gap in the application of elastic semiconductor single crystals in flexible organic light-emitting devices. Furthermore, as a protective material, it exhibits good performance stability, thus possessing high potential as a core material for flexible light-emitting devices. This invention expands the range of materials selected for flexible organic light-emitting devices, with broad application prospects, high value, and a promising market outlook.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor material preparation technology, and specifically discloses an elastic semiconductor single crystal, its preparation method, and its electroluminescence application. Background Technology

[0002] Organic semiconductor crystals, with their long-range molecular order and extremely low defect density, are highly attractive alternatives to thin-film materials and have been widely used in high-performance optoelectronic applications. Since Pope et al. first achieved electroluminescence in anthracene crystals in 1963, organic light-emitting single crystals have been used in various device structures, such as organic light-emitting diodes (OLEDs), field-effect transistors (OFETs), and polarization photodetectors. However, their inherent mechanical brittleness and poor strain tolerance make them prone to fracture upon deformation, severely limiting their application in next-generation flexible devices. Flexible molecular crystals are emerging as a potential solution to this challenge and have been successfully applied in various optoelectronic applications, such as light transmission media, X-ray radiation imaging, optical sensing, actuators, soft robotics, organic transistors, second harmonic generation, and piezoelectric materials. Despite these advances, the reported flexible crystals are typically needle-like or ribbon-like morphologies, posing a significant challenge to the fabrication of flexible single-crystal organic light-emitting diodes (FSC-OLEDs).

[0003] As key semiconductor performance indicators for FSC-OLEDs, flexible semiconductor single crystals possessing both high photoluminescence quantum yield and considerable charge carrier mobility are extremely rare. This scarcity stems from a fundamental reason: simultaneously achieving excellent flexible bending properties, efficient light emission, and outstanding conductivity within a single crystal stack is extremely difficult. For example, most flexible crystals reported to date exhibit excellent photoluminescence properties suitable for optical waveguides and amplifying spontaneous emission, while only a very few also exhibit meaningful conductivity. Therefore, despite strong technological motivations, realizing FSC-OLEDs based on flexible semiconductor single crystals remains a significant challenge.

[0004] The above challenges have hindered the application of flexible semiconductor single crystals in the field of flexible light-emitting diodes. Summary of the Invention

[0005] The purpose of this invention is to provide an elastic semiconductor single crystal, its preparation method, and its electroluminescent application, so as to solve the problems existing in the prior art.

[0006] The technical solution adopted in this invention is as follows: A single-crystal elastic semiconductor material, wherein the single-crystal material is 2,7-diphenyl-9 H-fluorene (DPhF), its structural formula is as follows: .

[0007] The preparation method of the above-mentioned elastic semiconductor single crystal material includes the following steps: Step S1: Dissolve 2,7-dibromofluorene, phenylboronic acid and tetra(triphenylphosphine)palladium(O) in 40 mL of toluene, then add potassium carbonate solution, and reflux at high temperature for a period of time under nitrogen protection to obtain crude product; Step S2: The crude product was subjected to silica gel column chromatography with a mixed solvent of petroleum ether and dichloromethane as the eluent, and then subjected to rotary evaporation to obtain DPhF white powder. Step S3: Dissolve DPhF white powder in a mixed solution of dichloromethane and ethanol at room temperature, and slowly evaporate for a period of time to obtain large-sized single crystals of DPhF. Step S4: Disperse DPhF white powder in chloroform solution, then add n-butanol to form a layered system, and grow flexible micro-sized single crystals of DPhF under isothermal conditions.

[0008] Furthermore, in step S1, the concentration of the potassium carbonate solution is 2 mol / L, the high-temperature reflux temperature is 85 ℃, and the time is 48 h; In step S2, the volume ratio of petroleum ether to dichloromethane in the mixed solution of petroleum ether and dichloromethane is 5:1. In step S3, the volume ratio of dichloromethane to ethanol is 2:1, and the evaporation time is 5 to 7 days. In step S4, the constant temperature condition is 35 ℃.

[0009] The above-mentioned elastic semiconductor single crystal materials are used in the fabrication of electroluminescent devices.

[0010] Furthermore, micro-sized single crystals of the elastic semiconductor single crystal material DPhF are used as the light-emitting layer of electroluminescent devices.

[0011] Furthermore, the electroluminescent device is a flexible light-emitting diode.

[0012] Furthermore, the above-mentioned method for fabricating the electroluminescent device includes the following steps: Step Sa: Select flexible PET / ITO as the conductive substrate and deposit a layer of MoO3 by vacuum thermal evaporation to change the hole injection energy level; Step Sb: Drop micro-sized single crystals of DPhF, a pre-grown elastic semiconductor single crystal material, onto a MoO3 substrate using a pipette, while simultaneously using a capillary to quickly remove excess solvent around the micro-sized single crystals. Step Sc involves coating a polymethyl methacrylate (PMMA) polymer insulating layer around the micro-sized single crystal, followed by the sequential deposition of functional layers in a high-vacuum evaporation system.

[0013] Furthermore, in step Sc, the functional layers include TPBi, LiF, and Al functional layers, wherein the TPBi layer is approximately 50 nm thick with a deposition rate of 1 Å / s, the LiF layer is approximately 100 nm thick with a deposition rate of 0.1 Å / s, and the Al layer is 150 nm thick with a deposition rate of 5 Å / s.

[0014] Furthermore, the electroluminescent device structure includes a PET substrate, an indium tin oxide (ITO) layer, a molybdenum trioxide (MoO3) layer, a micro-sized single crystal layer of the elastic semiconductor single crystal material DPhF, a 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi) layer, a lithium fluoride (LiF) layer, and an aluminum (Al) layer stacked sequentially. Among them, the thickness of the ITO layer is 200 nm, the thickness of the MoO3 layer is 2 nm, the thickness of the DPhF micro-sized single crystal layer is 600-1000 nm, the thickness of the TPBi layer is 50 nm, the thickness of the LiF layer is 1 nm, and the thickness of the Al layer is 150 nm.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) By designing the molecular structure and controlling the stacking structure of the elastic semiconductor single crystal material DPhF, the single crystal material is made to have excellent elastic flexibility, and its elastic bending curvature can reach 1 mm (see attached). Figure 2 As shown in the figure, the elastic semiconductor single crystal material DPhF was successfully applied in FSC-OLED, filling the gap in the application of elastic semiconductor single crystals in the field of flexible organic light-emitting devices.

[0016] (2) This invention, by combining mechanical property testing, synchrotron radiation micro-focused single-crystal X-ray diffraction (SCXRD), and photoelectric performance measurement, clearly reveals the molecular mechanism of elastic bending of DPhF single-crystal material, and effectively evaluates the device performance of this material under strain, ensuring the reliability of material applications. By calculating the local crystal structure at the bending position of the single crystal, it is clearly concluded that the carrier transport channel remains intact during elastic bending, and this conclusion is rigorously confirmed by dynamic Monte Carlo (KMC) simulation based on the experimentally determined bending crystal structure, further ensuring the performance stability of the material and device.

[0017] (3) The elastic semiconductor single crystal material DPhF provided by the present invention has the advantages of high purity and mechanical robustness. As the core material of flexible light-emitting device, it shows great application potential. Finally, the FSC-OLED electroluminescent device that can work stably under mechanical bending conditions was successfully prepared, which solved the technical problem of poor flexibility of traditional semiconductor single crystal and performance degradation of device after bending.

[0018] (4) In addition, based on the technical solution of the present invention, the development of flexible organic light-emitting diodes based on elastic semiconductor single crystals has been realized, which expands the material selection range of flexible organic light-emitting devices. Its application prospects are broad and it can be effectively applied to multiple fields such as flexible information display and wearable devices. It has significant industrial application value and market prospects. Detailed Implementation

[0019] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Wherein: Figure 1 The chemical molecular structure and proton NMR spectrum of the elastic semiconductor single crystal material in Example 1 of this invention are shown.

[0021] Figure 2 The images show the elastic bending photographs and nanoindentation diagrams of the elastic semiconductor single crystal material in Example 1 of the present invention.

[0022] Figure 3 This diagram illustrates the stacking structure and bending mechanism of the elastic semiconductor single crystal material in Example 1 of the present invention.

[0023] Figure 4 This is a diagram showing the carrier mobility at the bending position of the elastic semiconductor single crystal material in Example 1 of the present invention.

[0024] Figure 5 This is a schematic diagram of the fabrication process and structure of the flexible single-crystal-based light-emitting diode device in Embodiment 2 of the present invention.

[0025] Figure 6 The electroluminescence spectrum, current efficiency, luminous intensity, and external quantum efficiency of the flexible single-crystal-based light-emitting diode in Example 2 of the present invention are shown.

[0026] Example 1 (1) Organic molecular structure design of DPhF, an elastic semiconductor single crystal material This embodiment proposes a structural design method for the elastic semiconductor single-crystal material DPhF, and synthesizes a single-crystal material of an organic small molecule semiconductor—2,7-diphenyl-9. H -fluorene (hereinafter referred to as DPhF).

[0027] The preparation method is as follows: Step S1: Dissolve 2,7-dibromofluorene, phenylboronic acid and tetra(triphenylphosphine)palladium(O) in 40 mL of toluene, then add 2 mol / L potassium carbonate solution, and reflux at 85 °C for 48 h under nitrogen protection to obtain crude product; Step S2: The crude product obtained in step S1 is subjected to silica gel column chromatography, using a mixed solvent of petroleum ether and dichloromethane in a volume ratio of 5:1 as the eluent to obtain DPhF white powder. Step S3: Dissolve the white DPhF powder obtained in step S2 in a mixed solution of dichloromethane and ethanol with a volume ratio of 2:1 at room temperature, and slowly evaporate for 5 to 7 days to obtain large-sized single crystals of DPhF. It should be noted that the length of the large-sized single crystals of DPhF ranges from 5 to 20 mm, and the width ranges from 0.1 to 5 mm. Step S4: Disperse DPhF white powder in chloroform solution, then add n-butanol to form a layered system, and grow flexible DPhF micro-sized single crystals under constant temperature of 35℃. It should be noted that the length of the DPhF micro-sized single crystals ranges from 500 to 1000 μm and the width ranges from 150 to 300 μm. These DPhF micro-sized single crystals can be used to fabricate flexible light-emitting diodes.

[0028] like Figure 1 As shown, the micro-sized single crystals of DPhF prepared in this embodiment exhibit a linear, long rod-shaped planar conjugated framework. This molecular framework, with fluorene as its core, provides a rigid planar framework while maintaining the overall planarity of the molecule. The fluorene rings connect two benzene ring units at positions 2 and 7, extending the degree of planar conjugation and providing a certain degree of rotational freedom—essential for the bending of elastic crystals. This ultimately results in a linear, long rod-shaped planar conjugated molecule with a high aspect ratio. The combination of planar conjugated molecular structure and a large aspect ratio promotes one-dimensional chain stacking, a key structural prerequisite for elastic flexibility.

[0029] (2) Regulation of stacking structure of elastic semiconductor single crystals In addition, such as Figure 3As shown in (a) to (d), the high planarity of the linear rod-shaped molecules ultimately leads to a slower crystal growth rate along the long molecular axis (c-axis of the crystal) and a faster growth rate perpendicular to the molecular plane (b-axis of the crystal). This results in a fishbone-like stacking pattern, which not only maintains tight π-π interactions between molecules but also forms rapid carrier transport channels on the ab-plane of the crystal. Consequently, this exhibits high absolute quantum yield and carrier mobility.

[0030] Controlling the crystal stacking structure through molecular structure design is the fundamental means to realize elastic semiconductor single crystals. This not only achieves the elastic flexibility required for single crystals but also enables high-efficiency light emission and excellent carrier transport performance.

[0031] Example 2 like Figure 5 As shown in (a), the fabrication of a flexible light-emitting diode (FSC-OLED) based on the elastic semiconductor single-crystal material DPhF is described: Step Sa: Using flexible PET / ITO as a conductive substrate, a 2 nm thick layer of MoO3 is deposited by vacuum thermal evaporation at a rate of 0.1 Å / s to change the hole injection energy level; Step Sb: The micro-sized single crystal of the elastic semiconductor single crystal material DPhF (i.e. the product of step S4 in Example 1) that has been grown by solution method in advance is dropped onto the MoO3 substrate using a pipette, while the excess solvent around the micro-sized single crystal is quickly aspirated with a capillary tube. Step Sc: Then, a polymethyl methacrylate (PMMA) polymer insulating layer is coated and formed in the peripheral region of the DPhF micro-sized single crystal to cover the edge of the DPhF micro-sized single crystal. Subsequently, functional layers are deposited sequentially in a high vacuum evaporation system to obtain FSC-OLED.

[0032] like Figure 5 As shown in (b), the functional layers include TPBi, LiF, and Al functional layers. The TPBi layer is approximately 50 nm thick with a deposition rate of 1 Å / s, the LiF layer is approximately 100 nm thick with a deposition rate of 0.1 Å / s, and the Al layer is 150 nm thick with a deposition rate of 5 Å / s.

[0033] The electroluminescent device structure of this embodiment includes a PET substrate, an indium tin oxide (ITO) layer, a molybdenum trioxide (MoO3) layer, a micro-sized single crystal layer of the elastic semiconductor single crystal material DPhF, a 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi) layer, a lithium fluoride (LiF) layer, and an aluminum (Al) layer stacked sequentially. The thickness of the ITO layer is 200 nm, the thickness of the MoO3 layer is 2 nm, the thickness of the DPhF micro-sized single crystal layer is 600–1000 nm, the thickness of the TPBi layer is 50 nm, the thickness of the LiF layer is 1 nm, and the thickness of the Al layer is 150 nm.

[0034] Example 1 like Figure 2 As shown in (a), the semiconductor single-crystal material DPhF obtained in Example 1 exhibits a needle-like shape (length: 5~15 mm; width: 0.1~1 mm), or, as shown in (a), it is needle-like. Figure 2 As shown in (b), it has a narrow, sheet-like shape (length: 10~20 mm; width: 0.5~5 mm) and can be reversibly bent without breaking, exhibiting elastic flexibility with a bending curvature of up to 1 mm. Figure 2 As shown in (c), nanoindentation tests were performed on a Bruker Hysitron TI Premier system equipped with Berkovich indenters. Three points were selected on the crystal surface of the elastic semiconductor single crystal material DPhF for testing to obtain the elastic modulus and hardness at each point. Nanoindentation measurements performed on the (001) surface showed relatively high elastic modulus and average hardness, with an average elastic modulus of 11.885 GPa and a hardness of 0.342 GPa.

[0035] Microfocused X-ray diffraction (XRD) was performed on the DPhF to determine the crystal structure of the bent crystal. The XRD data were measured at 100(2) K on a synchrotron beamline with a wavelength λ = 0.7108 Å and a beam cross-section (half maximum full width at half maximum) of 10 × 11.25 μm. The DPhF semiconductor single crystal was pre-bent. Data was acquired at 40° (wedge-shaped) at the top of the bent crystal, at 25 locations spaced 2 μm apart from the inside to the outside of the bent crystal. Several locations near the crystal edge partially detached from the sample, and only 14 structures were successfully processed. The data were integrated using XDS, processed using SHELXT, and refined using SHELXL.

[0036] like Figure 3As shown in (e), a significant increase of 0.86% is observed along the b-axis along the crystal length from the inside to the outside, while a corresponding decrease of 1.3% is observed along the a-axis. Meanwhile, the changes observed along the c-axis and in the cell volume are small, indicating some uncertainty. To investigate the molecular origin of these cell variations, the evolution of the crystal structure at bends was analyzed. Figure 3 As shown in (g), the angle (θ) between molecules in a one-dimensional chain arranged along the b-axis, measured from a plane passing through each fluorene ring, decreases by 6.7%. This occurs when these molecules rotate outward from the inside of the bend, as... Figure 3 As shown in (f), elongation occurs in the b-axis direction because the C13-C13 distance (d) between molecules in adjacent one-dimensional chains increases by 0.89%, a value comparable to the 0.86% increase observed in the b-axis direction. This molecular movement promotes the corresponding contraction observed in the a-axis direction. Therefore, for the bending mechanism of the elastic semiconductor single-crystal material DPhF crystal, as... Figure 3 As shown in (h), this is mainly attributed to the rotation of molecules and the movement of these one-dimensional chains extending along the b-axis.

[0037] To assess the intrinsic effects of elastic bending on charge transport in DPhF single crystals, we performed dynamical Monte Carlo (KMC) simulations using an experimentally determined crystal structure under bending conditions (from inside to outside). A 10 × 10 × 4 supercell was employed, and the rates input to the KMC model were evaluated at the Fermi Golden Rule (FGR) level. We chose FGR to evaluate the rates because, compared to the widely used classical Marcus theory, it accounts for tunneling effects and frequency variations between the initial and final electronic states, including the entire set of normal modes in the calculations, resulting in highly reliable radiative and nonradiative electronic transition rates. In the simulations, we also considered the effects of thermal fluctuations in the transfer integral, which has proven to be a significant factor influencing charge mobility.

[0038] like Figure 4 As shown in (a), for an unbent crystal, the calculated charge carrier mobility is (0.24 ± 0.02 cm² / V). Figure 4As shown in (b), charge mobility at different locations in the bent crystal was calculated. The results show that the calculated charge carrier mobility exhibits only a slight, gradual increase from the inside to the outside (locations 4 to 20). Although some minor fluctuations were observed, they were all within the estimated error range. This behavior is perfectly consistent with the elastic and disorder-free characteristics of bending deformation, which maintains both long-range crystal order and the integrity of the π-conjugated framework. Furthermore, the effect of an external electric field equivalent to that applied in the FSC-OLED experiment was investigated. The presence of this field resulted in a small and uniform increase in the calculated mobility, consistent with the expected field-assisted hopping effect, but did not alter the dependence on the bending location: the mobility increased slightly from the inside to the outside regardless of the applied field, without drastic changes, indicating that the bending insensitivity of charge transport is unaffected by the driving electric field. In summary, these findings suggest that elastic bending does not fundamentally impair charge transport within the DPhF crystal.

[0039] Example 2 like Figure 6 As shown in (a), the performance of the FSC-OLED prepared in Example 2 was tested. Its emission spectrum was good, with an initial voltage of 35V. The emission intensity gradually increased with increasing driving voltage, reaching its peak at 410nm, which is consistent with the photoluminescence spectrum. Figure 6 As shown in (b), the overall current efficiency and luminous intensity also increase with increasing voltage.

[0040] like Figure 6 As shown in (c), the maximum EQE reached nearly 0.2%, which indicates that the FSC-OLED has excellent luminescence performance.

[0041] This invention designs and fabricates an elastic semiconductor single-crystal material, DPhF, and uses this material as the light-emitting layer to fabricate a flexible organic light-emitting diode (OLED). The single-crystal bending curvature can reach 1 mm, the absolute quantum efficiency is 82%, and the carrier mobility is 0.24 cm⁻¹. 2 / Vs, the electroluminescence wavelength is located in the blue light band of 410 nm, the EQE can reach 0.2%, and the bending curvature of the FSC-OLED device is less than 5 mm.

[0042] In summary, the elastic semiconductor single-crystal material DPhF designed in this invention has the following structural and performance characteristics: A linear, rod-shaped planar conjugated molecular structure that effectively enhances one-dimensional chain stacking, achieving the elastic and flexible mechanical properties required for single crystals.

[0043] Based on the chemical molecular structure of the elastic semiconductor single-crystal material DPhF, the high planarity of the linear rod-shaped molecules results in a slower crystal growth rate along the long molecular axis and a faster growth rate perpendicular to the molecular plane. This leads to a fishbone-like stacking pattern, which not only maintains tight π-π interactions between molecules but also forms rapid carrier transport channels within the crystal's ab plane. Consequently, this single crystal exhibits high absolute quantum yield and carrier mobility.

[0044] The elastic semiconductor single-crystal material DPhF can not only achieve elastic flexible bending, but also maintain its single-crystal long-range ordered structure under bending conditions, and the overall molecular framework does not undergo severe deformation, thereby obtaining stable carrier transport performance and high-efficiency light-emitting performance, and finally realizing the fabrication of flexible single-crystal organic light-emitting diodes.

[0045] In summary, this patented technology solves the difficulties in fabricating flexible semiconductor single crystals and the challenges in applying them to flexible organic light-emitting diode devices. It is expected to promote the application of flexible semiconductor single crystal-based flexible light-emitting diodes in next-generation information display and wearable devices.

[0046] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A single-crystal elastic semiconductor material, characterized in that, The single crystal material is 2,7-diphenyl-9 H -fluorene (DPhF), its structural formula is as follows: 。 2. The method for preparing an elastic semiconductor single crystal material according to claim 1, characterized in that, Includes the following steps: Step S1: Dissolve 2,7-dibromofluorene, phenylboronic acid and tetra(triphenylphosphine)palladium(O) in 40 mL of toluene, then add potassium carbonate solution, and reflux at high temperature for a period of time under nitrogen protection to obtain crude product; Step S2: The crude product is subjected to silica gel column chromatography with a mixed solvent of petroleum ether and dichloromethane as the eluent, and then subjected to rotary evaporation to obtain DPhF white powder. Step S3: Dissolve the DPhF white powder in a mixed solution of dichloromethane and ethanol at room temperature, and slowly evaporate for a period of time to obtain large-sized single crystals of DPhF. Step S4: Disperse the DPhF white powder in chloroform solution, then add n-butanol to form a layered system, and grow flexible micro-sized single crystals of DPhF under constant temperature conditions.

3. The method for preparing an elastic semiconductor single crystal material according to claim 1, characterized in that, In step S1, the concentration of potassium carbonate solution is 2 mol / L, the temperature of high-temperature reflux is 85 ℃, and the time is 48 h; In step S2, the volume ratio of petroleum ether to dichloromethane in the mixed solution of petroleum ether and dichloromethane is 5:

1. In step S3, the volume ratio of dichloromethane to ethanol is 2:1, and the evaporation time is 5 to 7 days. In step S4, the constant temperature condition is 35 ℃.

4. The application of the elastic semiconductor single crystal material according to claim 1 in the fabrication of electroluminescent devices.

5. The application according to claim 4, characterized in that, The micro-sized single crystal of the elastic semiconductor single crystal material DPhF is used as the light-emitting layer of the electroluminescent device.

6. The application according to claim 4 or 5, characterized in that, The electroluminescent device is a flexible light-emitting diode.

7. The application according to claim 5, characterized in that, The method for fabricating the electroluminescent device includes the following steps: Step Sa: Select flexible PET / ITO as the conductive substrate and deposit a layer of MoO3 by vacuum thermal evaporation to change the hole injection energy level; Step Sb: The micro-sized single crystal of the elastic semiconductor single crystal material DPhF, which has been grown by solution method in advance, is dropped onto the MoO3 substrate using a pipette, while the excess solvent around the micro-sized single crystal is quickly aspirated with a capillary tube. Step Sc: Subsequently, a polymethyl methacrylate (PMMA) polymer insulating layer is coated around the micro-sized single crystal, followed by the sequential deposition of functional layers in a high-vacuum evaporation system.

8. The application according to claim 7, characterized in that, In step Sa, a 2 nm thick layer of MoO3 needs to be deposited by vacuum thermal evaporation at a rate of 0.1 Å / s to change the hole injection energy level.

9. The application according to claim 7, characterized in that, In step Sc, the functional layers include TPBi, LiF, and Al functional layers. The TPBi layer has a thickness of approximately 50 nm and a deposition rate of 1 Å / s, the LiF layer has a thickness of approximately 100 nm and a deposition rate of 0.1 Å / s, and the Al layer has a thickness of 150 nm and a deposition rate of 5 Å / s.

10. The application according to claim 7, characterized in that, The electroluminescent device structure comprises a PET substrate, an indium tin oxide (ITO) layer, a molybdenum trioxide (MoO3) layer, a micro-sized single crystal layer of the elastic semiconductor single crystal material DPhF, a 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi) layer, a lithium fluoride (LiF) layer, and an aluminum (Al) layer, which are stacked sequentially. The thickness of the ITO layer is 200 nm, the thickness of the MoO3 layer is 2 nm, the thickness of the DPhF micro-sized single crystal layer is 600–1000 nm, the thickness of the TPBi layer is 50 nm, the thickness of the LiF layer is 1 nm, and the thickness of the Al layer is 150 nm.

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